There is something wrong with the folding algorithm, an error of some sort (alternatively there is a bug in the flash programming).
I found this whilst solving my design “Sinking Sailing Ship” before publishing it in the Player Puzzles section. Flipping the basepair at 20-166 resets the basepair counter at the bottom of the screen.
I have not published it yet, would be hard for others to solve it with constraints of 0 basepairs of any basepair type
Below you find the shape notation and screen-dumps of before and after basepairflip:
.(((((((…)))…(((.((((((…(((…((((((…)))(((…))))))…)))…)))…(((…)))))).(((…)))(((…(((…(((…(((…)))(((…))))))(((…))))))(((…))))))…))))))).
I made the puzzle to try to beat the bot algorithms, but I expected to be able to fold and finish it first
It would be nice if anyone else could report whether they can reproduce the error or not.